In order to take full advantage of the clinical gene therapy opportunities offered by synthetic gene delivery systems, their efficacy needs to be improved, and one way to identify improved synthetic vectors is to screen a large number of candidate formulations in a quantitative, efficacy-indicating assay. For this purpose our laboratory has developed a high throughput in vitro assay which enables 3000 transfection conditions to be quantitatively evaluated per week. This assay has identified compounds from a library of 144 cationic lipids, which have greater transfection potency than the most active commercially available reagents. Although these potent reagents have considerable commercial potential they have two significant limitations. First, most of them are substantially inhibited by serum, and second, transfection efficiency in a subset of cell types is disappointingly low. In order to solve these problems we have identified several additives that can greatly improve the activity of cationic lipid reagents in the absence and presence of serum. The purpose of this proposal is to utilize our quantitative high throughput assay, to screen a large number of these additives for transfection enhancing activity. The most effective additives will be prepared for commercial distribution. PROPOSED COMMERCIAL APPLICATIONS: The resources from this grant will be used to make more potent transfection reagents commercially available to academic scientist and the pharmaceutical industry. Production methods and analytical quality control assays will be conducted to validate the product. These products will be of interest to cell and molecular biologist requiring a more efficient DNA transfection agent, and to pharmaceutical and academic scientist interested in developing gene therapy treatments.